// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2009 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_BENCH_TIMERR_H
#define EIGEN_BENCH_TIMERR_H

#if defined(_WIN32) || defined(__CYGWIN__)
#ifndef NOMINMAX
#define NOMINMAX
#define EIGEN_BT_UNDEF_NOMINMAX
#endif
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#define EIGEN_BT_UNDEF_WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
#elif defined(__APPLE__)
#include <mach/mach_time.h>
#else
#include <unistd.h>
#endif

static void
escape(void* p)
{
#if EIGEN_COMP_GNUC || EIGEN_COMP_CLANG
	asm volatile("" : : "g"(p) : "memory");
#endif
}

static void
clobber()
{
#if EIGEN_COMP_GNUC || EIGEN_COMP_CLANG
	asm volatile("" : : : "memory");
#endif
}

#include <Eigen/Core>

namespace Eigen {

enum
{
	CPU_TIMER = 0,
	REAL_TIMER = 1
};

/** Elapsed time timer keeping the best try.
 *
 * On POSIX platforms we use clock_gettime with CLOCK_PROCESS_CPUTIME_ID.
 * On Windows we use QueryPerformanceCounter
 *
 * Important: on linux, you must link with -lrt
 */
class BenchTimer
{
  public:
	BenchTimer()
	{
#if defined(_WIN32) || defined(__CYGWIN__)
		LARGE_INTEGER freq;
		QueryPerformanceFrequency(&freq);
		m_frequency = (double)freq.QuadPart;
#endif
		reset();
	}

	~BenchTimer() {}

	inline void reset()
	{
		m_bests.fill(1e9);
		m_worsts.fill(0);
		m_totals.setZero();
	}
	inline void start()
	{
		m_starts[CPU_TIMER] = getCpuTime();
		m_starts[REAL_TIMER] = getRealTime();
	}
	inline void stop()
	{
		m_times[CPU_TIMER] = getCpuTime() - m_starts[CPU_TIMER];
		m_times[REAL_TIMER] = getRealTime() - m_starts[REAL_TIMER];
#if EIGEN_VERSION_AT_LEAST(2, 90, 0)
		m_bests = m_bests.cwiseMin(m_times);
		m_worsts = m_worsts.cwiseMax(m_times);
#else
		m_bests(0) = std::min(m_bests(0), m_times(0));
		m_bests(1) = std::min(m_bests(1), m_times(1));
		m_worsts(0) = std::max(m_worsts(0), m_times(0));
		m_worsts(1) = std::max(m_worsts(1), m_times(1));
#endif
		m_totals += m_times;
	}

	/** Return the elapsed time in seconds between the last start/stop pair
	 */
	inline double value(int TIMER = CPU_TIMER) const { return m_times[TIMER]; }

	/** Return the best elapsed time in seconds
	 */
	inline double best(int TIMER = CPU_TIMER) const { return m_bests[TIMER]; }

	/** Return the worst elapsed time in seconds
	 */
	inline double worst(int TIMER = CPU_TIMER) const { return m_worsts[TIMER]; }

	/** Return the total elapsed time in seconds.
	 */
	inline double total(int TIMER = CPU_TIMER) const { return m_totals[TIMER]; }

	inline double getCpuTime() const
	{
#ifdef _WIN32
		LARGE_INTEGER query_ticks;
		QueryPerformanceCounter(&query_ticks);
		return query_ticks.QuadPart / m_frequency;
#elif __APPLE__
		return double(mach_absolute_time()) * 1e-9;
#else
		timespec ts;
		clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
		return double(ts.tv_sec) + 1e-9 * double(ts.tv_nsec);
#endif
	}

	inline double getRealTime() const
	{
#ifdef _WIN32
		SYSTEMTIME st;
		GetSystemTime(&st);
		return (double)st.wSecond + 1.e-3 * (double)st.wMilliseconds;
#elif __APPLE__
		return double(mach_absolute_time()) * 1e-9;
#else
		timespec ts;
		clock_gettime(CLOCK_REALTIME, &ts);
		return double(ts.tv_sec) + 1e-9 * double(ts.tv_nsec);
#endif
	}

  protected:
#if defined(_WIN32) || defined(__CYGWIN__)
	double m_frequency;
#endif
	Vector2d m_starts;
	Vector2d m_times;
	Vector2d m_bests;
	Vector2d m_worsts;
	Vector2d m_totals;

  public:
	EIGEN_MAKE_ALIGNED_OPERATOR_NEW
};

#define BENCH(TIMER, TRIES, REP, CODE)                                                                                 \
	{                                                                                                                  \
		TIMER.reset();                                                                                                 \
		for (int uglyvarname1 = 0; uglyvarname1 < TRIES; ++uglyvarname1) {                                             \
			TIMER.start();                                                                                             \
			for (int uglyvarname2 = 0; uglyvarname2 < REP; ++uglyvarname2) {                                           \
				CODE;                                                                                                  \
			}                                                                                                          \
			TIMER.stop();                                                                                              \
			clobber();                                                                                                 \
		}                                                                                                              \
	}

}

// clean #defined tokens
#ifdef EIGEN_BT_UNDEF_NOMINMAX
#undef EIGEN_BT_UNDEF_NOMINMAX
#undef NOMINMAX
#endif

#ifdef EIGEN_BT_UNDEF_WIN32_LEAN_AND_MEAN
#undef EIGEN_BT_UNDEF_WIN32_LEAN_AND_MEAN
#undef WIN32_LEAN_AND_MEAN
#endif

#endif // EIGEN_BENCH_TIMERR_H
